Session 2: Nanotechnology
Chair: Pascal Verbiest, Umicore, BENanotechnology is still a controversial term in material development, dividing the coatings industry into enthusiastic supporters and sceptics. Nevertheless a lot of research is being done in order to obtain functional and high performance coatings, as this session shows. Scientific approaches make use of functionalised sols, hybrid organic and inorganic materials, solvent-free supramolecular liquids, alternating anhydride reactive fluoro-comb polymers, dispersing carbon nano-tubes or nanoparticles.
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Monday Afternoon 14.00 – 17.30 h
Room Istanbul
2.1 14.00 – 14.30 h Functionalized sols for industrial applications Dr. Harald Lutz, CHT, DE Of the numerous nanotechnological processes the Sol-Gel process is gaining importance. The manufacturing of Sol-Gel products is outlined in brief, and the synthesis of innovative, aqueous sols which are commercially available is described more in detail. The functionalities of the presented Sol-Gel products can be controlled either by choosing appropriate metal centres or different organic groups. These effects are illustrated by various examples and the profiles of the sols are defined. Different applications demand different principles of crosslinking on corresponding surfaces. The crosslinking can be initiated by temperature profile, change of pH value, light exposure et al. After the presentation of the crosslinking principles technical applications of different industrial segments are discussed.  | ||
| 2.2 14.30 – 15.00 h Ultra thin coating of surfaces with quarternary ammonium groups containing polyamines via polyelectrolyte complex formation Dr. Andrea Körner, DWI an der RWTH Aachen e.V., DE One of the central tasks for future technologies is the modification of surfaces and interfaces. Here we report on the amino functionalization of polyamines and on the coating of various surfaces from aqueous solution to form durable, monomolecular thin films (Figure 1). Negatively charged groups are found on the surface of nearly all materials; if necessary, these can be generated by mild plasma treatment or UV irradiation. Compounds with ammonium groups will form highly stable polyelectrolyte complexes with these surfaces which are resistant towards high ionic strengths and extreme pH values. A new class of polymers containing both quaternary ammonium groups and an excess of reactive primary amine groups was developed. Cyclic functionalized carbonates with quaternary ammonium groups were synthesized and polymer analogous reactions with suitable amino polymers, in this case polyethylenimines (PEI), chitosan and wool keratin peptides with a high portion of ε-amino functional amino acids, were performed. | ||
| 2.3 15.00 – 15.30 h Polymer-grafted silica nanoparticles for improving mechanical resistance of coatings Gerhard Jonschker, Merck KGaA, DE The demands are high, placed on coatings concerning mechanical toughness. Scratches are a well-known problem which are disturbing especially on glossy and dark surfaces. For a long time now, inorganic nanoparticles have been discussed as a way to increase the scratch resistance. However, at present the realization is often limited because compatibility problems occur during processing, such as agglomeration, haze and increased viscosity. A new approach from Merck are core-shell particles, leading on the one hand to a remarkable increase in scratch resistance and which are on the other hand very easy to process and show a compatibility like an organic resin. This profile was realized by covalently attached polymer chains on the nanoparticle surface. The functionalized polymers react with the binder matrix and thus after curing the nanoparticles become an integral part of the coating itself. By anchoring the polymer shell on the nanoparticle surface, the disturbing inorganic character of the nanoparticle core is masked. The result is a so far unknown compatibility making the use of dispersion aids dispensable. Concentrations of 1 3 wt% are often enough for realizing a significant increase in scratch resistance without affecting the other coatings properties. 15.30 – 16.00 h Networking: Refreshments & Coffee Break | ||
| 2.4 16.00 – 16.30 h Solvent-free supramolecular liquids for novel resins and applications Prof. John Texter, Eastern Michigan University, US Nanoscale colloidal particles when suitably surface functionalized form solvent-free supramolecular liquids or nanofluids that exhibit melting and crystallization, glass transition, and solubilization phenomena. When we further functionalize such nanofluids to make them suitably reactive, new classes of resins and coatings are obtained. When such nanofluids are functionalized with acrylate groups and mixed with other acrylate monomers, zero VOC coating formulations are obtained that can be used to make clear coats curable by UV. When isocyanate or isothiocyanate functionalized nanofluids are made and mixed with diisocyanates, zero VOC coatings can be made that air cure into protective resins. Amine surface functionalization produces nanofluids that can be used to produce UV-resistant epoxy coatings when co-solubilized with aliphatic diglycidyl ethers. Suitable chemistries are described for applying such functionalization to nanocolorants, special effect colorants, carbon blacks, as well as silica, for specialized coatings applications and for large volume advanced materials. | ||
| 2.5 16.30 – 17.00 h Dispersing carbon nano tubes - a challenge on the way to functional coatings Dr. Michael Berkei, BYK-Chemie GmbH, DE Carbon Nano Tubes are probably the most exciting material that has been discovered in the 20th century. Starting as a curiosity, production capacity has been increased within the last few years to the hundreds of tons range to meet the rising market demands. The material exhibits very interesting properties and can functionalise coatings in terms of mechanical reinforcement, anti-static properties and conductivity. Due to their high aspect ratio up to a few thousand, carbon nano tubes tend to agglomerate in a way that can be described as clews and bundles. To achieve a high impact, the tubes need to be homogeneously distributed inside the coating. Therefore, the right dispersion technique in combination with suitable wetting and dispersing additives is key. | ||
| 2.6 17.00 – 17.30 h Using nanoparticles as dispersants for microparticles Erik Thiele, DuPont, US The "Nano-Particle Halo Effect" is a newly recognized means by which a colloid made of micron sized particles can be stabilized against flocculation using highly charged nano-particles. The nano-particles preferentially occupy the region close to the micron sized particles without attaching to the micron sized particles, creating a halo of charge. The micron sized particles repel one another due to this charge in the same way that is seen in conventional electrostatic stabilization of a colloid (the important difference being that in the former case the charge units are not on the pigment surface, but instead surround the pigment). Application of the Halo Effect to TiO2 dispersion will be discussed, with examples of successful and unsuccessful nano-particle performance. | ||
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